Flexural Strength of Satellite Teeth Cut by a Nonstandard Tool in a Planetary Gear

Russian Engineering Research - A method is proposed for determining the radius of curvature of transition curves in satellite-teeth profiles of planetary gears with internal engagement. The teeth...     

Influence of the content of radioactive wastes with high concentrations of aluminum,sodium, and iron oxides on the phase composition and structure of glassy materials prepared in a “cold crucible”

The vitrification of a high-level waste surrogate with high concentrations of aluminum, sodium, and iron oxides in a “cold crucible” results in the formation of glassy materials with the phase composition and structure dependent on the ratio between waste oxides and borosilicate glass frit. With an increase in the waste content from ∼50 to ∼66 wt %, the degree of crystallinity of the materials increases from ∼5 to 50 vol %. The main crystalline phase is spinel, and the additional crystalline phase is nepheline. The amount of the nepheline increases with an increase in the waste content in glassy materials and with a decrease in the rate of their cooling in heat-insulated molds. The spinel is the main concentrator of transition elements (Cr, Mn, Fe, Ni, Cu, Zn). A considerable fraction of sodium, aluminum, and silicon transfers into the formed nepheline, which leads to the depletion of the glass phase in oxides of these elements and to a decrease in its chemical durability.     

Production of the STA2-encoded glucoamylase in Saccharomyces cerevisiae is subject to feed-back control

Three modes of production of the extracellular glucoamylase (GA) in Saccharomyces cerevisiae have been identified; repressed, basal and induced. The repressed mode is found with cells grown in rich media containing non-limiting concentrations of monosaccharides or disaccharides, including GA-hydrolysable maltose, as a sole carbon source. Both the basal and the induced modes (spanned by some seven-fold differences in the rate of GA production) can be displayed by either glucose-limited or glycerol-plus ethanol-consuming cultures; the induced mode is switched over to the basal one due to a feed-back inhibition by extracellularly accumulated GA. It is proposed that the feed-back control involved in GA production can be attenuated by starch which can thus 'induce' higher rates of GA production compared to the basal mode.     

Hydrodynamics of flow past spheres in a bed

Substantiation is given for a theoretical-experimental scheme for a coherent, concise generalization of data on the hydraulic resistance of random and regular beds of spherical particles.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 59, No. 6, pp. 979–984, December, 1990.     

Active thermal testing of hyperthermoconductive panels

Application of active infrared thermography to assessing the internal structure and functioning of hyperthermoconductive panels used in on-board electronics is described. Effective thermal- diffusivity maps of hyperthermoconductive panels, obtained using the pulsed Parker method, are presented. The peculiarities of heat transfer in hyperthermoconductive panels are illustrated using experimental modeling in which a local thermal-load source is placed on the surface of hyperthermoconductive panels.     

Parameter Optimization of Two-Speed Manual Drive with Automatic Speed Change for Stop Valves

Chemical and Petroleum Engineering - A flexible shaft planetary gear drive for valve actuators, providing automatic gear shifting based on load, is proposed. The design features two wheels...     

Influence of Planetary-Gear Structure on the Load Distribution

A method is proposed for determining the load in the gear engagements of a multiflux planetary gear with flexible carrier jaws. The influence of the design and manufacturing errors of the mechanism on the pliability of its components and the nonuniformity of the load distribution over the satellites is determined.